An apparatus for removing molten mass from the rear bottom portion of items is known from German Patent No. DE 440 677. The known apparatus includes two adjacent conveyor belts with a gap portion being located therebetween. The apparatus includes a solid shaft having a small outer diameter which serves to remove a part of the molten mass from the gap portion between the two adjacent conveyor belts. The shaft is located in the gap portion and at a small distance below the conveying path. The conveying path is formed by the surfaces of the two adjacent conveyor belts. The shaft is supported by bearings being located outside of the working width of the conveyor belts. The shaft is driven to rotate at a number of revolutions in a range of approximately 1,000 revolutions per minute. The mass tends to form edges or tails by flowing down from the rear portion of the items when the items are located in the gap portion between the two conveyor belts. When the mass flows a little further down than the conveyor plane in the gap region due to gravity, this part of the coating mass contacts the surface of the solid shaft, and it is removed thereby. In other words, the molten and kneadable mass is torn away, the torn away part of the mass being wound up and being removed, respectively, by the solid shaft.
The known apparatus attains a good effect when being used in combination with comparatively big and long, respectively, items such as bars or cookies. Due to the fact that the length of the items in the conveying direction has to be chosen not to be too small due to the gap between two adjacent conveyor belts, there is the possibility of choosing the diameter of the solid shaft to be comparatively great. This leads to the solid shaft having sufficient stability even when driving it at comparatively great numbers of rotations. This especially applies to small working widths, meaning working widths below 600 mm. When using greater working widths and especially when conveying items which are comparatively short as seen in the conveying direction, as for example brandy beans or brandy cherries, the width of the gap between two adjacent conveyor belts has to be chosen to be very small to allow for the short items to pass the gap portion as desired. In case the working width of the apparatus is additionally chosen to be great, for example in a range of between 1,000 and 2,000 mm, the known apparatus causes problems. There are vibrations occurring at the shaft which necessarily has a small diameter and which is comparatively long. The shaft tends to flutter and to lift off such that it does no longer fulfill its function. This danger especially applies to the middle portion of a long shaft. The desired effect of removing the edges in the rear bottom portion of the items is no longer attained in the middle portion.
The shaft may be supported on a heated stripper sheet metal which is arranged to be stationary and to be approximately vertical. The stripper sheet metal is arranged at an angle with respect to the shaft such that the removed mass is transferred from the shaft to the stripper sheet metal. Due to heating of the stripper sheet metal and the generation of heat caused thereby which act upon the shaft, the removed mass remains in the molten state such that it may flow down due to gravity to be reintroduced into the circuit of the coating machine. The surface of the shaft is continuously cleaned from mass by the stripper sheet metal.
To prevent fluttering, lifting off and displacement effects of the shaft with respect to the stripper sheet metal, it is known to arrange bearing lugs, clamps, wire loops and the like in a spaced apart manner such that they at least partly encompass the shaft and which function as additional stationary bearings for the shaft within the working width. In addition to these additional bearings, the shaft with its ends is additionally supported in two end bearings being located outside of the working width of the conveyor belts. The bearing lugs, clamps and the like have the negative effect that either the distance between the two conveyor belts in the gap portion is enlarged or the diameter of the shaft has to be reduced in a respective way. In case the bearing lugs, clamps and the like also surround the shaft at its upper surface, meaning the surface facing the conveying path, it is only possible to a limited extent to arrange the shaft comparatively close to the upper surface of the conveying path and to the end and to the beginning of the two conveyor belts. As a result, the distance in a vertical direction and in a horizontal direction is comparatively great which leads to the effect of comparatively short edges or tails of molten mass no longer being contacted and removed by the shaft. The major disadvantage of such bearing lugs, clamps and the like however is that it is possible that mass builds up on them, the mass smearing and negatively influencing the bottom of such goods which pass the place where the bearing lugs are arranged as they are conveyed on the conveyor belts. In case the coating machine is only designed for one certain product and the items are transported in predetermined rows, there is the possibility or arranging the bearing lugs between the rows of items. However, when processing various products in the coating machine, this is not possible. In addition, one always needs to reckon that even predetermined rows of items may change their position in a lateral direction such that the items nevertheless contact the bearing lugs. In the region in which the bearing lugs act upon the shaft, the shaft loses its removing function, or this function is at least negatively influenced to a great extent. Furthermore, it is disadvantageous that the bearing lugs, clamps and the like which may be supported and arranged on the stripper sheet metal in a stationary way have to be designed to be very thin due to the above described conditions. They are elements which are immediately subjected to wear and tear and which need to be replaced rather often. Especially when the bearing lugs are designed to be closed, replacement of the shaft and/or of the bearing lugs requires substantial disassembly and assembly work during which the coating machine cannot be used for production. Especially, shafts which are driven to rotate at a great number of rotations may be deformed to become eccentric during normal operation and especially when foreign matter reaches the region between the shaft and the stripper sheet metal. Such eccentricity deforms the shaft in a way that it can no longer be used and that it needs to be replaced. Only in rare cases it is possible to straighten such an eccentric shaft outside of the coating machine such that the shaft can be further used. Usually, the shafts need to be replaced by new shafts. The replacement takes a substantial amount of time during which at least the two bearings located at the ends and outside of the working width need to be disassembled to get access to the shaft.
An apparatus for removing molten mass, especially chocolate mass, from the rear bottom portion of items is known from German Patent No. DE 43 22 414 C1 corresponding to European Patent No. EP 0 632 962 B1. A driven solid shaft extending over the working width of the apparatus is arranged in the gap portion between two adjacent conveyor belts. A heated stripper sheet metal is arranged below the shaft in a stationary way and at an approximately vertical orientation. The shaft is supported on the stripper sheet metal, and it is cleaned from surplus mass by the stripper sheet metal. The shaft is kept in place and supported on the stripper sheet metal due to magnetic forces. In this way, one not only attains a supporting function of the shaft on the stripper sheet metal, but one also realizes a more or less continuous support for the shaft on the stripper sheet metal, the support extending over the working width. Due to magnetic attraction between the shaft and the stripper sheet metal, it is furthermore ensured that the shaft is located at a certain angle with respect to the stripper sheet metal and that the stripper sheet metal can fulfill its stripping and cleaning effect for the shaft during rotation of the shaft about its axis. The magnetic forces may however also act upon the region where the two conveyor belts are deflected in a way to cause attraction and repulsion effects between the shaft and the conveyor belts which may lead to a negative displacement of the shaft. To prevent this, the distance may not fall below a certain minimum value. The outer diameter of the shaft cannot be chosen as small as this would be desired for small items.